Question: Which of these numbers is composite? ${11,\ 23,\ 31,\ 38,\ 47}$
A composite number is a number that has more than two factors (including 1 and itself). 11, 23, 31, and 47 each have only two factors. The factors of 38 are 1, 2, 19, and 38. Thus, 38 is the composite number.